Method of and apparatus for making phonograph records



July 24, 1923.

G. ALLEGRETT! METHOD OF AND APPARATUS FbR MAKING PHONOGRAPH RECORDS Original Filed Jan. 22, 1921 INVENTOR. 6' A llegfre 25!} BY Q E E ATTORNEY Patented July 24, 1923,

U res i'rEo GIACOMO: ALLEGRET'II, or STOCKTON, cnnrnoanm.

ivrnrnonwor nun APPARATUS non MAKING- rrronoenarn nnconns.

. I Application filed January 22, 1921, Serial To aZZ wZwm z't may concern h Beit'known that I, .GIACOMO ALLEGRETTI,

. a citizen of the United-States, residing at Stockton, county of San Joaquin, State of California, have invented certain new and useful Improvements in Methods of and Apparatus. for Making Phonograph Records;and I do declare the following to .be a full, clear, and exact description of the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this application,

This invention relates toimprovements in phonograph-record making, the principal object being to devise what maybe termed a. phono-engraving process, and' an apparatus by means of.;which the process may be carried out. I 1

By means of my invention, master'phonograph records may be produced directly and without the necessityof first recording the sounds on a soft wax, which necessitates a number of subsequent operations before the individual records are made.-

My method may therefore also be used by individual owners, who may. desire. to make theirown records, which heretofore to my knowledge has beenqimpractical, at least withoutincurring considerable. expense and in a complicated way. r I am also enabled to regulate the depth of cutting of the record, so that the volume ofsound finally reproduced may be varied. withoutnecessarily increasing the original sound-volume,f,the vibrations produced by which .cause the record to becut.

Further, I am not limited to the use of the wax composition. now generally used for records, but may employ anymaterial which can be etched by acids and which may bev made in a form suitable for my purpose. I

Briefly, I contemplate, as, indicated in the preceding paragraph, etching the surface of a blank by means of acidsjsuitablegfor the purposa the acid, being deposited on the blank. "in ;minute drops' of? various sizes,

' which then eat into the blank to correspond ingf and varying depfli$,'the depositing of the acid being re ulated and controlled by the strength of t e sound wavesor vibration'sl received, into a transmitter, which is rovidedfwith means cooperating with the no. 433,188. Renewed December 28, 1922.

acid to cause it to be deposited as aforestated.

The above described method is employed the blank, stays on the surface, hardening thereon, so that female records as universally used can be made directly therefrom.

A further object of the invention is to produce a'simple and inexpensive device and yet one which will be exceedingly effective for the purposes which it is designed.

These objects I accomplishby'means of such structure and relative arrangement of parts as will fully appear by a perusalof the following specification and claims.

'In the drawings similar characters of ref erence indicate corresponding parts'in the several views. p

i Fig. 1 is a sectional view of one form of sound-vibration transmitter.

- Fig. 2 is a greatly enlarged fragmentary section of the recording tip or point.

Fig. 3 is a sectional view of another form of the device.

Fig. 4: is a greatly enlarged fragmentary section of a recording blank, showing the depositing of the liquid thereon.

Fig. 5 is a similar view showing the de pressions made by the liquid inthe blank after acting thereon.

Referring now more particularly to the characters ofreference on the drawings, the numeral 1 denotes a circular base member supported for any desired and necessary the horn 5 is a hollowtip or tube 6, prefers ably of glass or some material which is not afi'ected by acids. Both the bore 7 ofthis tip andthe outside as well taper down to the lower end to be as small as it is possible for:

it to be made. r

7 Fixed to the diaphragm 4L and depending into the bore 7 to a point adjacent the lower termination thereof is a pin 8 (Fig. 1) the bore being filled with a suitable acid 9, the amount of acid depending on the length of the record to be cut.

In operation, the tip is set into and guided by a groove 10 cut previously in the surface of a'recording blank 11 which may be of any material desired-which is suitable for the purpose and can beetched with an acid, the latter of course beingone which has a great afiinity for the particular record-material em loyed. I

en sounds are produced and carried into thehorn 5, the diaphragm of coursevibrates correspondingly; as is well known. The pin' '8 moving up and down with the diaphragm causes minute drops of the acid to be projected from the bottom of the tip. into the record groove 10, the size and length of these drops bearing a distinct relation to the magnitude and length of the soundwaves, as indicated at 12on Fig. l. If left undisturbed, these acid drops will etch or eat into the blank to form depressions of various lengths and depths as shown at 13 in Fig. 5', which cor-respond to the drops deposited, while the depth to whichthey cut (and consequently the volume of sound which may be reproduced) depends on the time given the acid to act, and the strength thereof, these being matters to be determined.

If a soft record is desired, the acid may be wiped or cleaned off the record before it has expended its full strength. If a loud record is wanted, the acid is left to act for a longer-period.

Also the angle at which the tip will strike the record is a matter to be determined by experiment.

In the event that the droplets of any acid should exhibit a tendency to flow together, the viscosity, and hence the surface tension of the fluid may be increased by mixing it with another fluid of a heavier nature.

In the form of transmitter or recorder shown in Fig. 3', the main structure remains as before.

The pin 8 however, does not extend to the bottom of the tip, but terminates a certain distance above the liquid, and is provided with a piston Mat that point, which is spaced just sufficiently from the walls of the tip-bore to allow air to pass thereby.

With this form of construction, the rapid vibration of the diaphragm causes vertical movement of the piston, which acts on the air below, which in turn causes the acid to be projected from the end of the tip in minut ops, s here ofo e exp ain Q In both types of the device, the tip-bore is in reality a capillary tube, which means that the liquid will not of itself flow from the tip, but will if anything be normally raised therein, until forced out by the action of the pin or piston.

By adjusting the cover 3 in either case, the positions ofthe pin and piston are varied accordingly, thus increasing or decreasing the intensity of their action on the record-blanks, but it may" alsobeused to cut a record on the edge of motion picture film, opening the way for speaking pictures, which have heretofore been attempted but with indifferent success,

In making master records, the etching fluid or acid is replaced by a 'substancesuch as rubber dissolved in ether, which when projectedfrom the tube and exposed to the air will solidify and harden, remaining on the surface of the blank without eatingthereinto, asshown in Fig. 4. In this case of course the blank must" not badisturbed in any way until the substance thereon has solidified.

From the foregoing. descriptionit will be readily seen "that Ihave produced such a device as substantially fulfills the objects of the invention as set forth herein.

WVhile this specification sets forth in detail the present and preferred construction of the device, still-in practice such deviations from such detailmay be resorted to; as do not form a departure rrcmthe spirit of the invention, as defined by the appended claims.

Having thus described my invention,what I claim as new and useful and desire to se-. cure by Letters Patent isi 1. An apparatus fonthe purpose-described including a diaphragm adapted to be acted on by the sound-waves produced, a capillary tube containing an etching fluid p0, sitioned underthe diaphragm, said tube beingplaced immediately adjacent the recordblank to be etched, and means connected to the diaphragm and acting on the liquidfor causing the liquid to-be projected from the tube in minute drops bearing a distinct relation to the magnitude and'length of the d-Wa es causing the di phra m to brate, H V 7 s I, j

2. An apparatusfor'the purpose described u ng d p mgm' apt d. to e act y t e soiihd w ves P duce api lary ub n a n ng a etching fluid pos i ned nder. the diaphra m. said tube b ing placed mmedia ely adiac htthe record-hl kt be tc e and. pin attache to and, dep nd-r. its fr m the d aphragm" into the; tube and ar anged o fereethe iquid, from. the at er. nd to the reQQrd-hlan n. m nnte rop (is pending on'the magnitude and length of the sound Waves causing the diaphragm and pin to move.

3. An apparatus for the purpose described including a diaphragm adapted to be acted 5 on by the sound-Waves produced, a

ca illary tube containing an etching fluid, positioned under the diaphragm, said tube bein immediately adjacent the record- 5 placed blank to In testimony whereof I aifix my signature.

GIACOMO ALLE GRETTI. 

